Which process turns metamorphic rocks into magma?

• A. Weathering
• B. Metamorphism
• C. Melting
• D. Compaction

Answer: (C)

Melting is the process that turns metamorphic rocks into magma. When rocks are subjected to high enough temperatures (and sometimes fluids), they can reach their melting point and begin to liquefy. In the crust, partial melting often produces a mixture of liquid magma and solid crystals; this molten material can collect and rise because magma is less dense than surrounding rock, potentially forming igneous bodies or erupting as lava at the surface. Weathering breaks rocks into sediments; metamorphism alters mineralogy and texture without necessarily turning rock into liquid magma; compaction squeezes sediments into sedimentary rock. So the direct way a metamorphic rock becomes magma is through melting.